Writing instrument



Jan. 28, 1930. G. w. BLACKBURN WRITING INSTRUMENT Filed May 15, 1925 Patented Jan. 28, 1930 TES GUY W. BLACKBURN,

OF ELGIN, ILLNOIS WRTING INSTRUMENT Application led may l5,

My invention relates to a means for writing and particularly to a means for writing upon combustible substances by the local application of heat. Other objects will appear a from time to time throughout the course 0f the specification and claims.

My invention is illustrated more or less diagrammatically in the accompanying drawings, where1n-' Figure l is a longitudinal section through the writing implement;

Figures 2 and 3 are sectional details of variations;

Figure 4 is a side elevation with parts broken away of a Variant form;

Figure 5 is an axial section through a variant form of instrument.

Like parts are indicated by like characters throughout the specification and drawings.

Referring to Figure l, A is any suitable body or casing of conducting material herein shown as cylindrical. One end is screw threaded as at A1 to receive the cap A2.v The opposite end is inwardly turned as at As and provided with a screw threaded sleeve A4 forwardly projecting therefrom, said portion being screw threaded both internally and externally.

B is any suitable battery or series of batteries having a forward exposed contact B1 and being forwardly thrust for example by the spring B2 compressed against the cap A2. The cylindrical sides of the battery are perfectly covered by an insulating material B3. Mounted in the interior of the cylinder A and adapted to support a resistance coil or wire B5 having a plurality of contacts B", is a clip B4 of insulating material. The wall of the cylinder is longitudinally slotted thereabove, as at B7, the slot being closed by the slide B8 controlled by the handle B. B10 is a contact on the slide opposed to the contacts B1" associated with the resistance coil.

C is any suitable plug or supporting means of insulating riaterial internally screw threaded in the sleeve A4 and having an interior contact C1 opposed to the battery contact B1. The plug is apertured to permit the passage therethrough of the wire C2 which 50 may be suitably covered orinsulated and i925. Serial No. 30,488.

which extends inwardly from the plug, and is in circuit with the resistance wire B.

D is an inner plug screw threaded as at D1 into the central aperture of the plug C and axially apertured to permit the passage of si;d the wire D2 extending through to the contact C1. The wires D2 and C2 are in circuit and included in their circuit is any suitable resistance element herein illustrated as the coiled wire D3. This wire is located in the en hollow D* of the enlarged tip D5 of the plug D. This plug or its tip is preferably` composed of material adapted for the ready transmission of heat.

E is any suitable cap or shield internally es screw threaded as at E1 and upon the sleeve A and adapted to surround all but the extreme tip of the member D5. It is preferably of material adapted to serve as an insulant against the transmission both of electricity and heat. Another function of the insulated cap E is to prevent the tip D5 burning deep enough to catch in the paper or to burn through more than one sheet.

Referring to Figure 2, a slightly variant form of plug corresponding to the plug C is illustrated.

G is the body of the plug apertured to permit the passage of the wires G1 G2 in circuit with the resistance member G3, herein shown Q as a bent wire of somewhat greater cross section than the wires G1 G2. The plug G is shaped to conform to the interior of the shield E and is adapted to be screw threaded into the sleeve A4.

The corresponding plug H of Figure 3 terminates in a hemispherical surface H1 upon which is mounted the heniispherical cap H2 of resistance material. H3 H4 are wires in circuit therewith whereby it may be put in 9o circuit with'the battery or other power source.

Referring to Figure 4, a form of pen is illustrated in which the current from afixed power source may be employed.

J is the cylindrical body of the pen having connected thereto the flexible cord J1 containing the inleading and outleading wires J 2 J 3. Any suitable tip J 4 is employed covered by the shield J 5. Js is a switch or contact adapted to be engaged by the stud J' 100 on the manually controllable slide J 8 it being understood that when the contacts J 8 and J l are closed the current flows through the tip J4 or any suitable resistance member adapted to heat it. t

Referring to Figure 5, K is the cylindrical body of the pen and K1 the forward protecting shield. Screw threaded into it is the plug K2 with a central contactor element K3 opposed to the battery contact K4. The pen nib K5 is placed in contact therewith. Mounted on the insulating plug K2 is the spring or contact member K6 adapted to contact the sleeve K7 and thus to be in circuit with the casing K, which is of conducting material. K5 and Ke are so placed and proportioned that only when pressure is actually exerted upon the pen are they in contact and is the circuit closed. Their opposed tips are preferably of resistant material which, with the closing of the gap between the two, results in the immediate development of local heat in response to pressure upon the pen. material employed is preferably heat resistant in order that it may not be destroyed or fused as a result of the heat so generated.

It will be evident that while I have shown in my drawings an operative device still many changes might be made in the size, shape, number and disposition of parts without departing materially from the spirit of my invention and I wish, therefore, that my showing be taken as in a sense diagrammatic.

lThe use and operation of my invention are as follows: v

In making permanent records it is desirable to have the'mark made by the recording instrument as imperishable as possible. It should be able to resist both the chemical and physical changes caused by time. It is particularly important, in connection with documents or records involving the payment of sums of money, that the indicating marks be dicult to change or remove. In my apparatus for making such records I make an impression on a combustible or a carbonizable substance by the local application of heat. The surface of the paper or their receiving medium is chemically changed, and the mark -is made without the superposition of any additional substance. Pencil marks and ink marks, which are merely bodies of foreign.

, fect a more or less thin inlay of carbon is left, the top of the carbon being flush with the surface of the paper. `The carbon is, of

The

course, of different color than the surrounding body of the paper and may be as readily legible as an ink mark. If it is removed it leaves an indentation of the paper. Under some circumstances it may be advantageous to make the impression so deep as practically to pass through the `paper. An attempt to remove the impression, in such case, leaves the original marks inthe form of perforations, and alteration thereof is peculiarly hard.

I am able to write fine lines by this method. since the area exposed to the heat is extremely small, the Writing tip being insulated except at a single point. Furthermore, as the paper chars, and the thin layer of carbon forms, or is separated from the body of the paper by Athe driving off of the other components, the carbon so formed is an admirable insulant kagainst heat and itself limits the spread of the charring. By varying the chemical composition of the paper written upon, it is possible to vary the color of the impression, since some papers char brown and others black.

I may make the closing of the heat circuit respond'directly to pressure on the pen, as

shown in Figure 5 or I may provide positive of the battery passes through the element D3.

Under some circumstances this reaction is important since the faster the writ-ing the greater the heat and the current necessary to make a legibleimpressure. In Figure 4 I illustrate a form wherein the circuit used may be taken from a fixed power source, for example, the ordinary house circuit.

' I claim:

l. In a pen, a hollow handled casing, adapted to contain a battery, a resistance element mounted on said casing, a circuit including a resistance element and said battery, and means for making and breaking it, adapted to close said circuit during the actual writing operation comprising a flexible nib'and a contact opposed theretosaid nib adapted to be moved against said contact in response to the pressure of writing.

2. In a pen, a handle member, a resistance.

element mounted thereon, a source of elect-ric energy therefor, a circuit including said resistance element and said source of energy, and means for making and breaking it adapted to close said circuit during the actual writing operation comprising a flexible nib and a contact opposed thereto, said nib adapted to be moved against said contact in response to the pressure of writing.

3. In combination, a pen and an electric circuit connected therewith, a point comprising a resistance element and means for passing current through said circuit and throu h said pen, said circuit adapted to be closed 1n response to the pressure of Writing.

4. In an instrument for making permanent 5' records upon a combustible surface, an element and means for heating it, a shield, re-

sistant to the passage of heat, substantially surrounding said element, said shield being penetrated by an aperture of small cross section, the heated element projecting slightly through said aperture, the relative proportions of aperture and heated element being such that a relatively small tilting of the Writing instrument suices to lift the heated glement from contact with the opposed surace.

Signed at Chicago, county of Cook, and State of Illinois, this 29th rlay of A ril, 1925.

GUY W. BLACKURN. 

